Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
In optical lithography, a pattern may be formed on a substrate using a mask. In some examples, a light sensitive photoresist layer may be applied to the substrate. A light source may apply a beam of light to the substrate through the mask. The pattern on the mask may cause the light beam to expose some areas of the photoresist and block other areas of the photoresist from exposure based on the pattern. The photoresist may react to the applied light to form the pattern on the substrate. An optical system may be interposed between the mask and the substrate allowing for changes in a size of the pattern exposed to the photoresist layer.